History of Life

Question 1

define macroevolution

Answer 1

broad pattern of change above a species level

Question 2

what does macroevol tell us about

Answer 2

emergence of terrestrial vertebrates, mass extinctions, origin of flight in birds

Question 3

when did earth form

Answer 3

4.6 bya

Question 4

did early earth have lots of O2

Answer 4

no

Question 5

process how life originated

Answer 5

1. abiotic synthesis of small organic molecules
2. joining of smaller mlecules into macromolecules such as proteins and NA
3. Packaging of macromolecules into protocells(droplets w/ membrane that separated inside protocell from external env)
4. Origin of self-replicating molecules that eventually made inheritcance possible

Question 6

what is the fossil record biased towards

Answer 6

1. hard animals
2. widespread distribution
3. lived for long

Question 7

what are the 4 major eons

Answer 7

Hadean, Archaean, Protozeric, Phanerozoic

Question 8

hadean

Answer 8

beginning of planet to 4 bya

Question 9

archaean

Answer 9

4 bya to 2.5 bya

Question 10

proterozoic

Answer 10

2.5 bya-.5 bya

Question 11

phanerozoic

Answer 11

.5 bya-present

Question 12

what eras is the phanerozoic divided into

Answer 12

paleozoic, mesozoic, cenozoic

Question 13

what organisms have dominated life for the majority of time

Answer 13

microbes

Question 14

when did the first single-celled organism form

Answer 14

3.5 bya

Question 15

what were earth’s sole inhabitants for 1.5 by

Answer 15

Prokaryotes (bacteria + archaea)

Question 16

what are the oldest known fossils and when

Answer 16

stromatolites(3.6 bya)

Question 17

when did O2 begin accumulating

Answer 17

2.7 bya from photosyntehsizing organisms

Question 18

when was the O2 rev

Answer 18

2.7-2.3 bya
inc O2 levels by 3-4 orders
some were poisoned by this- many prok went extinct

Question 19

when were the first eukaryotes

Answer 19

1.8 bya via endosymbiosis

Question 20

when were the first multicellular euk

Answer 20

small algae 1.2 bya

Question 21

larger and more diverse euk(plants, animals, fungi) not in fossil record until….?

Answer 21

600 mya

multiellularity evolved independelty

Question 22

cambrian explosion

Answer 22

small window of time(10 million)
btwn protozoic and phanerozoic
appearance of fossils resembling modern animals
first evidence of predator prey interactions in fossil record
soft bodies appeared after

Question 23

colonizing land

Answer 23

500 mya- fungi, animals, plants on land
420 mya- vascular tissue in plants
365 mya- tetrapods evolved from fish
6-7 mya- origian of human lineage from chimps
200,000 ya- origin of modern humans

Question 24

what has influenced patterns of diversity

Answer 24

plate tectonics, mass extinctions, adaptive radiation

Question 25

effects of continental drift on living organism

Answer 25

alters habits in which organisms live, climate on continent could change based on latitude, separation of land masses leads to allopatric speciation

Question 26

fossils and continental drift

Answer 26

distribution of fossils and living groups relfect historic mbmt of continents
before 135 mya, fossils shared siilarity in parts of south American and africa…..were formerly attached

Question 27

mass extinctions

Answer 27

vast majority of species ever lived on spanet now extinct(99.9%)
caused by change to a species env
result of disruptive, global, env change
5 majors ones, each with > 50% marine life going extinct

Question 28

Permean and cretaceous ME

Answer 28

Permian- biggest extinction, 251 mya, btwn paleozoic and mesozoic, volcanism, extinction of 96% oF MArine animals

Cretaceous- not as severe, 65 mya, between mesozoic and cenozoic, 50% of marine species went extinct and dinos went extinct, percentage of marine organisms that were predators increased

Question 29

define adaptive radiation

Answer 29

rapid speciation rate for 1 lineage from a common ancestor

Question 30

adaptive radiation

Answer 30

shape distribution of species diversity of organisms
lineages w. novel and advantageous features can be lost during mass extinctions
ME can pave way for AR
usually follows: ME, evol of novel characteristics, and colonization of new regions

Question 31

global AR

Answer 31

mammals had one after dino extinction

other radiations: photosynthetic prok, large predators in cambrian, land plants, flying insects, waking tetrapods

Question 32

regional AR

Answer 32

occupy particular regions, not worldwide
organisms colonize new env w/ little comp
ex. hawaiian islands drosophila

Question 33

macroevolution allow for what?

Answer 33

study of traits
traits and novel traits evolve by tinkering
most novel traits/structures evolve in many stages from previously existing structures
NS an only improve a structure in context of current utility

Question 34

evolutionary novelties

Answer 34

complex eyes have evolved from simple photosensitive cells independently many times
modern day mollusks show eye structure from patch of pigmented cells to complex lens

Question 35

evolutionary trends

Answer 35

extracting a single evol progression from fossil record can be misleading
apparent trends should be examined ina broader context
does not imply an intrinsic arive toward a specific ptype

Question 36

what are the key events in life’s history

Answer 36

origins of unicellular and multicellular organisms and colonization of land

Question 37

diversity patterns of diff groups of organism reflect differences in ?

Answer 37

speciation

Question 38

is evol goal oriented?

Answer 38

NO! but selection is